Metastatic infection during Staphylococcus aureus bacteremia.

Staphylococcus aureus causes various infections, including skin and soft tissue infections and pneumonia via both, community-associated and nosocomial infection. These infectious diseases can lead to bacteremia, and may subsequently result in metastatic infections in several cases. Metastatic infections are critical complications in patients with S. aureus bacteremia, since the optimal duration of the antimicrobial treatment differs in patients with and without metastatic infection. Notably, two weeks of antimicrobial treatment is recommended in case of uncomplicated S. aureus bacteremia, whereas in patients with S. aureus bacteremia-associated endocarditis or vertebral osteomyelitis, six weeks of antimicrobial administration is vital. In addition, misdiagnosis or insufficient treatment in metastatic infection is associated with poor prognosis, functional disability, and relapse. Although echocardiography is recommended to examine endocarditis in the patients with S. aureus bacteremia, it remains unclear which patients should undergo additional examinations, such as CT and MRI, to detect the presence of other metastatic infections. Clinical studies have revealed that permanent foreign body and persistent bacteremia are predictive factors for metastatic infections, and experimental studies have demonstrated that the virulence factors of S. aureus, such as fnbA and clfA, are associated with endocarditis; however, these factors are not proven to increase the risk of metastatic infections. In this review, we assessed the incidence, predictive factors, diagnosis, and treatment for metastatic infections during S. aureus bacteremia.

Seroprevalence and associated factors of Toxoplasma gondii among HIV-infected patients in Tokyo: A cross sectional study.

HIV infection, in particular in patients with developing AIDS, carries a risk of causing toxoplasmosis with encephalitis, which is mostly caused by a form (bradyzoite) of the protozoan parasite Toxoplasma gondii. HIV/AIDS in Japan has been recognized as a serious health issue in recent years. In this study, to elucidate T. gondii seroprevalence in HIV-positive patients in Japan and associated characteristics with Toxoplasma parasite infection, the titer of T. gondii IgG (Tg-IgG) was measured in 399 HIV-positive patients who visited a hospital in Tokyo, Japan, between 2015 and 2017. A questionnaire survey was also conducted to investigate associations between lifestyle and customs. As a result, the overall prevalence of Tg-IgG-positive serum was 8.27% (33 cases of 399). All the cases positive for Tg-IgG were confirmed using the Sabin-Feldman dye test; the titers between each examination correlated robustly (p < 0.001, r = 0.6). A correlation between Toxoplasma infection rate and age was determined (p < 0.001), whereas there was no significant correlation with lifestyle customs such as consuming undercooked meat or owning a cat. An association between Toxoplasma infection and experience of dwelling in the Hokkaido area, the northern part of Japan, was observed (p = 0.001). These results suggested that the proportion of those who were previously exposed to Toxoplasma parasites in the HIV-positive population has been maintained at a similar level as that of the HIV-negative population in Japan, providing clear information about the potential risk of toxoplasmic encephalitis.

Age-Associated Theophylline Metabolic Activity Corresponds to the Ratio of 1,3-Dimethyluric Acid to Theophylline in Mice.

Age is known as one of influencing factor for theophylline (TP)-metabolizing capacity. In a previous our study, the ratio of TP and its major metabolite 1,3-dimethyluric acid (DMU) in serum (DMU/TP) is a useful index to estimate TP-metabolizing capacity, and this value markedly increased by influencing factor, such as the history of smoking. However, it is unknown whether DMU/TP values in serum reflect age-associated changes of TP-metabolizing capacity. In this study, the effect of age on the DMU/TP values in serum were investigated using mice of different age due to the limited blood sampling in human. The concentrations of TP and its metabolites in mouse serum were simultaneously measured using HPLC. As observed in human serum, serum TP concentrations were closely correlated with DMU concentration in mice, which indicates that the DMU/TP ratio is a good indicator of TP metabolic ability in mice. When TP was administered subcutaneously in 2-28-week-old mice, age-associated changes in the DMU/TP ratio in mice were observed. In conclusion, age-associated changes in TP-metabolizing capacity can be estimated by the DMU/TP ratio in serum.

Surveillance on susceptibility of strains isolated from pediatric infections.

During the period from January to December 2015, 104 Streptococcus pneumoniae strains, 129 Haemophilus influenzae strains and 54 Moraxella catarrhalis strains isolated from clinical specimens of pediatric infections in the national 16 institutions, studied susceptibilities of total 28 antibiotics, the capsular serotype for S. pneumoniae, the capsular b type and ß-lactamase production capability for H. influenzae, and the ß-lactamase production capability for M. catarrhalis were measured. In S. pneumoniae, the results showed that 68 strains (65.4%) were PSSP, 32 (30.8%) were PISP, and 4 (3.8%) were PRSP. The susceptibilities of TBPM and GRNX among oral antibiotics, and PAPM among injectable antibiotics demonstrated the lowest value with MIC90 ≤ 0.06 µg/mL. The most frequent distribution of S. pneumoniae serotypes was seen in 15B, followed by 19A, and 35B. Serotype strains contained in 13-valent pneumococcal conjugate vaccine (PCV13) were 19 strains (18.3%). In H. influenzae, the results showed that BLNAS accounted for 40 strains (31.0%), BLNAI for 28 strains (21.7%), BLNAR for 47 strains (36.4%), ß-lactamase producing for 14 strains (10.8%). The susceptibilities of quinolones demonstrated the lowest outcome among oral antibiotics with MIC90 ≤ 0.06 µg/mL, and CTRX and TAZ/PIPC (TAZ4 fixed) among injectable antibiotics with MIC of 0.25 µg/mL. There was no detection of capsular type b strains. In M. catarrhalis, all the isolates were ß-lactamase producing strains. The susceptibilities of TBPM, CPFX, TFLX and GRNX among oral antibiotics, and TAZ/PIPC (TAZ4 fixed), PAPM, MEPM and DRPM among injectable antibiotics demonstrated the lowest outcome with MIC of ≤0.06 µg/mL.

Detection of bacterial DNA from central venous catheter removed from patients by next generation sequencing: a preliminary clinical study.

BACKGROUND: Catheter-related infection (CRI) is one of the serious challenges in clinical practice. This preliminary clinical study aimed to examine whether next-generation sequencing (NGS) targeting 16S rDNA, which was PCR-amplified directly from the tip of a central venous catheter (CVC), can be used to identify causative pathogens in CRI, compared to the culture method. METHODS: Hospitalized patients, from whom a CVC had just been removed, were prospectively enrolled and divided into the CRI-suspected and routine removal groups. DNA was extracted from the sonication fluid of CVC specimens derived from patients. For analysis of bacterial composition by NGS, the V3-V4 fragments of bacterial 16S rDNA were PCR-amplified, followed by index PCR and paired-end sequencing on an Illumina MiSeq device. Conventional culture methods were also performed in the CRI-suspected group. RESULTS: Of CVCs collected from the 156 enrolled patients (114 men; mean age 65.6 years), a total of 14 specimens [nine out of 31 patients suspected with CRI and five out of 125 patients without infection symptoms (routine removal group)] were PCR-positive. In five patients with definite CRI, Staphylococcus was the most frequently detected genus by NGS (4/5 specimens), although no pathogens were detected by NGS in the one remaining specimen. The genera identified by NGS were consistent with those from conventional culture tests. There was high agreement between NGS and the culture method in the CRI-suspected group, with sensitivity and specificity values of 80.0% and 76.9%, respectively; meanwhile, the false-positive rate of NGS was as low as 4.0% in the routine removal group. Moreover, several genera, besides the genus identified by culture test, were detected in each patient with definite CRI and surgical site infection (SSI). Additionally, in one patient with SSI, Enterococcaceae were detected not only by NGS but also by abdominal abscess drainage culture. CONCLUSIONS: NGS targeting 16S rDNA was able to analyze the bacterial composition of CVC specimens and detect causative pathogens in patients with CRI and was therefore suggested as a promising diagnostic tool for CRI.

Pharmacokinetics and brain penetration of carbapenems in mice.

An adverse effect associated with the administration of carbapenems is central nervous system (CNS) toxicity, with higher brain concentrations of carbapenems being linked to an increased risk of seizures. However, the pharmacokinetics and brain penetration of carbapenems have not yet been examined. Thus, the aim of this in vivo investigation was to determine the pharmacokinetics and brain penetration of carbapenems in mice. Blood samples and brain tissue samples were obtained 10, 20, 30, 60, and 120 min after the subcutaneous administration of carbapenems (91 mg/kg). We obtained the following values for the pharmacokinetic parameters of carbapenems in mice: 1.20-1.71 L/h/kg for CLtotal/F, 1.41-2.03 h(-1) for Ke, 0.34-0.51 h for T1/2, 0.66-0.95 L/kg for Vss/F, 0.49-0.73 h for MRT, 83.46-110.58 µg/mL for Cmax, plasma, and 0.28-0.83 µg/g for Cmax, brain tissue. The AUC0-∞ of the carbapenems tested in plasma were in the following order: doripenem > meropenem > biapenem > imipenem, and in brain tissue were: imipenem > doripenem > meropenem > biapenem. The degrees of brain tissue penetration, defined as the AUC0-∞, brain tissue/fAUC0-∞, plasma ratio, were 0.016 for imipenem, 0.004 for meropenem, 0.002 for biapenem, and 0.008 for doripenem. The results of the present study demonstrated that, of the carbapenems examined, imipenem penetrated brain tissue to the greatest extent.

DSR-71167, a novel mineralocorticoid receptor antagonist with carbonic anhydrase inhibitory activity, separates urinary sodium excretion and serum potassium elevation in rats.

Mineralocorticoid receptor (MR) antagonists, such as spironolactone (SPI) and eplerenone (EPL), are useful for treating hypertension and heart failure. However, these two agents have the serious side effect of hyperkalemia. We hypothesized that adding the ability to inhibit carbonic anhydrase (CA) would reduce the risk of hyperkalemia associated with MR antagonists. We investigated the profiles of DSR-71167 [2-([(2,2-difluoroethyl)amino]methyl)-2'-fluoro-N-(3-methoxy-4-sulfamoylphenyl)biphenyl-4-carboxamide hydrochloride; an MR antagonist with weak CA inhibitory activity] with regard to antimineralocorticoid actions by examining relationships between the urinary excretion of sodium (index of antimineralocorticoid action) in deoxycorticosterone acetate-treated rats and elevation of serum levels of potassium in potassium-loaded rats compared with a DSR-71167 derivative without CA inhibition (2-(hydroxymethyl)-N-[4-(methylsulfonyl)phenyl]-2'-(trifluoromethyl)biphenyl-4-carboxamide), SPI, and EPL. DSR-71167 dose-dependently increased urinary excretion of sodium in deoxycorticosterone acetate-treated rats without elevating serum levels of potassium in potassium-loaded rats. 2-(Hydroxymethyl)-N-[4-(methylsulfonyl)phenyl]-2'-(trifluoromethyl)biphenyl-4-carboxamide, SPI, and EPL elevated serum levels of potassium significantly in potassium-loaded rats at doses that increased MR inhibitory activity. We confirmed that DSR-71167 significantly increases urinary bicarbonate and decreases blood bicarbonate, as pharmacodynamic markers of CA inhibition, in intact rats. Chronic DSR-71167 administration showed antihypertensive effects in high salt-loaded Dahl hypertensive rats. These results demonstrate that DSR-71167 is a novel type of MR antagonist, with CA inhibitory activity, which is expected to become a safer MR antagonist with a low potential risk for hyperkalemia.

Pharmacokinetics and dosing estimation of meropenem in Japanese patients receiving continuous venovenous hemodialysis.

The pharmacokinetics of meropenem have not yet been examined in Japanese patients receiving Continuous venovenous hemodialysis (CVVHD). The aim of this clinical investigation was to determine the pharmacokinetic parameters of meropenem in critically ill patients receiving CVVHD in order to estimate dosing regimens for the patient population in Japan. The values of pharmacokinetic parameters were 17.5 ± 5.6 l for V1, 1.27 ± 0.38 h(-1) for K12, 0.71 ± 0.40 h(-1) for K21 and 0.17 ± 0.02 h(-1) for K10. Based on these mean parameters (V1, K12, K21 and K10), time above MIC (T > MIC) values were estimated at different MICs using various meropenem regimens. For bacteria with a meropenem MIC of ≤ 2 µg/ml, a dosing regimen of 0.25 g every 24 h achieved more than 40% T > MIC. For a MIC of 4 µg/ml, all the regimens tested, except for 0.25 g every 24 h, achieved more than 40% T > MIC. For a MIC of 16 µg/ml, dosing regimens of 0.5 g every 8 h, 1 g every 12 h, and 1 g every 8 h achieved 40% T > MIC, reaching the pharmacokinetic-pharmacodynamic target range. This is the first study to examine the pharmacokinetics of meropenem under a CVVHD setting in Japan. The pharmacokinetic-pharmacodynamic profile of dosing regimens tested in this study will assist in selecting the appropriate meropenem regimens for patients receiving CVVHD.

Correlations between extent of X-ray infiltration and levels of serum C-reactive protein in adult non-severe community-acquired pneumonia.

Pneumonia cases can vary in both severity and chest X-ray findings. Elevated C-reactive protein (CRP) levels may be an indicator of disease severity. We retrospectively evaluated factors correlated with the extent of chest X-ray infiltration both in community-acquired pneumonia (CAP) and a subgroup of cases with pneumococcal pneumonia. In a clinical study that evaluated the efficacy of sitafloxacin, 137 patients with CAP had been previously enrolled. In our study, 75 patients with pneumococcal pneumonia were identified among these 137 CAP patients. The extent of chest X-ray infiltration was scored and correlations with age, sex, body temperature, white blood cell (WBC) count, and CRP levels were analyzed using multivariate analysis with logistic regression. Significant correlations were observed between the extent of chest X-ray infiltration and CRP levels in both CAP and pneumococcal pneumonia. Our data indicates that CRP is a valuable and informative resource that could reflect the severity of pneumonia in cases of both CAP and pneumococcal pneumonia.

Different dynamic movements of wild-type and pathogenic VCPs and their cofactors to damaged mitochondria in a Parkin-mediated mitochondrial quality control system.

VCP/p97 is a hexameric ring-shaped AAA(+) ATPase that participates in various ubiquitin-associated cellular functions. Mis-sense mutations in VCP gene are associated with the pathogenesis of two inherited diseases: inclusion body myopathy associated with Paget's disease of the bone and front-temporal dementia (IBMPFD) and familial amyotrophic lateral sclerosis (ALS). These pathogenic VCPs have higher affinities for several cofactors, including Npl4, Ufd1 and p47. In Parkin-dependent mitochondrial quality control systems, VCP migrates to damaged mitochondria (e.g., those treated with uncouplers) to aid in the degradation of mitochondrial outer membrane proteins and to eliminate mitochondria. We showed that endogenous Npl4 and p47 also migrate to mitochondria after uncoupler treatment, and Npl4, Ufd1 or p47 silencing causes defective mitochondria clearance after uncoupler treatment. Moreover, pathogenic VCPs show impaired migration to mitochondria, and the exogenous pathogenic VCP expression partially inhibits Npl4 and p47 localization to mitochondria. These results suggest that the increased affinities of pathogenic VCPs for these cofactors cause the impaired movement of pathogenic VCPs. In adult flies, exogenous expression of wild-type VCP, but not pathogenic VCPs, reduces the number of abnormal mitochondria in muscles. Failure of pathogenic VCPs to function on damaged mitochondria may be related to the pathogenesis of IBMPFD and ALS.

[Two cases of Paragonimiasis westermani in a Chinese family diagnosed with the Ouchterlony double diffusion method].

We report two cases of Paragonimus westermani infection in a Chinese family in Japan. A 41-year-old husband and his 40-year-old wife were infected with P. westermani after consuming a homemade Chinese traditional "Drunken Crab." They were a family with two children who had lived in Japan for 19 years. The crabs were Eriocheir japonica sent from the Kyusyu area that they had pickled at home with soy sauce and Chinese liquor for 5 days. Their children did not eat any of the crabs. One month after consuming the crabs, the husband came to our outpatient clinic with fever and chest pain and his wife also presented with a persistent cough. Both patients had a high peripheral blood eosinophil count (husband:18,900/µL, wife:10,600/µL) with pulmonary effusion, nodular shadow, and pneumothorax in chest X-ray findings. Paragonimiasis was suspected from the episode of consuming the crabs. No parasite eggs were seen in their sputum and stool samples. A multiple-dot ELISA was performed with the sera to screen for parasitic infections, but the result was only weakly positive for P. westermani antigen in the husband and a slightly positive reaction in the wife. The diagnosis of P. westermani was achieved with the double diffusion Ouchterlony method using P. westermani antigen and P. miyazakii antigen. Praziquantel administration for three days improved the symptoms in both patients. The Ouchterlony method proved useful in diagnosing paragonimiasis in these cases.

[Study on the safety and efficacy of sitafloxacin at a dose of 100 mg once a day--results of the use-results survey].

Sitafloxacin (STFX, Gracevit 50 mg, fine granules 10%), an oral quinolone antibacterial agent, was approved additionally for administration at a dose of 100 mg once a day in August 2011. A use-results survey on STFX 100 mg/day was performed from December 2011 to May 2013. In total, 1,186 case cards were collected from 226 medical institutions and 1,089 cases were subjected to a safety evaluation and 1,069 were subjected to an efficacy evaluation. The incidence of adverse drug reactions (ADRs) was 2.11% (23/1,089 cases) and no serious ADRs were observed. The major ADR was diarrhea at 1.10% (12/1,089 cases). Of these 12 cases, 10 cases developed symptoms within 4 days of treatment. All of them, except one case that could not be followed up, either recovered or improved. Nonsteroidal anti-inflammatory drugs of the phenyl acetate and propionate types, which require caution when coadministered with STFX, were used concomitantly by 17.6% (192/1,089 cases) of patients but no central nervous system ADRs were observed. The overall efficacy rate was 96.4% (1,030/1,069 cases) and by types of infections, it was 97.0% (387/399 cases) for respiratory tract infections, 96.7% (353/365 cases) for urinary tract infections, 94.7% (36/38 cases) for gynecological infections, 92.3% (132/143 cases) for otorhinolaryngological infections, 98.4% (122/124 cases) for dental and oral surgical infections. The efficacy rate in every category of site of infection exceeded 90%. The overall eradication rate was 94.4% (185/196 strains) including Gram-positive bacteria at 95.4% (62/65 strains), Gram-negative bacteria at 92.2% (94/102 strains), anaerobes at 100.0% (11/11 strains) and atypical bacteria at 100.0% (18/18 strains). In conclusion, this use-results survey confirmed that STFX 100 mg/day is an effective administration with no serious problems in its safety profile and efficacy rate of over 90% in every category of site of infection.

Pigmentation level of human iPSC-derived RPE does not indicate a specific gene expression profile.

Retinal pigment epithelium (RPE) cells show heterogeneous levels of pigmentation when cultured in vitro. To know whether their color in appearance is correlated with the function of the RPE, we analyzed the color intensities of human-induced pluripotent stem cell-derived RPE cells (iPSC-RPE) together with the gene expression profile at the single-cell level. For this purpose, we utilized our recent invention, Automated Live imaging and cell Picking System (ALPS), which enabled photographing each cell before RNA-sequencing analysis to profile the gene expression of each cell. While our iPSC-RPE were categorized into four clusters by gene expression, the color intensity of iPSC-RPE did not project any specific gene expression profiles. We reasoned this by less correlation between the actual color and the gene expressions that directly define the level of pigmentation, from which we hypothesized the color of RPE cells may be a temporal condition not strongly indicating the functional characteristics of the RPE.

The backs of our eyes are lined with retinal pigment epithelial cells (or RPE cells for short). These cells provide nutrition to surrounding cells and contain a pigment called melanin that absorbs excess light that might interfere with vision. By doing so, they support the cells that receive light to enable vision. However, with age, RPE cells can become damaged and less able to support other cells. This can lead to a disease called age-related macular degeneration, which can cause blindness. One potential way to treat this disease is to transplant healthy RPE cells into eyes that have lost them. These healthy cells can be grown in the laboratory from human pluripotent stem cells, which have the capacity to turn into various specialist cells. Stem cell-derived RPE cells growing in a dish contain varying amounts of melanin, resulting in some being darker than others. This raised the question of whether pigment levels affect the function of RPE cells. However, it was difficult to compare single cells containing various amounts of pigment as most previous studies only analyzed large numbers of RPE cells mixed together. Nakai-Futatsugi et al. overcame this hurdle using a technique called Automated Live imaging and cell Picking System (also known as ALPS). More than 2300 stem cell-derived RPE cells were photographed individually and the color of each cell was recorded. The gene expression of each cell was then measured to investigate whether certain genes being switched on or off affects pigment levels and cell function. Analysis did not find a consistent pattern of gene expression underlying the pigmentation of RPE cells. Even gene expression related to the production of melanin was only slightly linked to the color of the cells. These findings suggests that the RPE cell color fluctuates and is not primarily determined by which genes are switched on or off. Future experiments are required to determine whether the findings are the same for RPE cells grown naturally in the eyes and whether different pigment levels affect their capacity to protect the rest of the eye.

Dissolution profile of 24 levofloxacin (100 mg) tablets.

Although there are 23 generic levofloxacin (100 mg) tablets (LVFX tablets) and 1 brand name LVFX tablet (supply now discontinued) in Japan, there have been no reports that have evaluated and compared the dissolution profiles of LVFX tablets using the same dissolution method. We studied the dissolution profile of LVFX tablets by the Paddle method, a standard dissolution test method. Among 23 generic LVFX tablets, 2 LVFX tablets had lower dissolution rates and 14 had higher dissolution rates than the brand name LVFX tablet. It is suggested that LVFX tablets have different dissolution profiles, which could cause different pharmacokinetic profiles.

Clinical dose findings of sitafloxacin treatment: pharmacokinetic-pharmacodynamic analysis of two clinical trial results for community-acquired respiratory tract infections.

The adequacy of sitafloxacin clinical dose regimens was assessed by comparing the efficacy of the administration of 100 mg sitafloxacin once daily (100 mg qd group) and 50 mg sitafloxacin twice daily (50 mg bid group). Patients with respiratory tract infections caused by pneumococci were orally treated with sitafloxacin (100 mg qd or 50 mg bid) for 7 days. The clinical efficacy, pneumococci eradication rate, safety, and pharmacokinetic and pharmacodynamic indices of the two groups were then assessed. The clinical efficacy was 93.5 % in both groups. The pneumococci eradication rate was 98.2 % in the 100 mg qd group and 92.7 % in the 50 mg bid group. The mean of the free AUC0-24h divided by the minimum inhibitory concentration (MIC) (fAUC0-24h/MIC) did not differ significantly between the 100 mg qd (103.24) and the 50 mg bid groups (105.25). The mean of the free C peak divided by the MIC (fC peak/MIC) was higher in the 100 mg qd group (10.19) than in the 50 mg bid group (6.53). The pathogen eradication rate was 98.9 % (89/90) when the fAUC0-24h/MIC was greater than 30, and the eradication rate was 98.9 % (89/90) when the fC peak/MIC was greater than 2. The incidences of adverse drug reactions were 33.7 % in the 100 mg qd group and 40.4 % in the 50 mg bid group. No obvious differences in the efficacy and safety were observed between the dosage groups. For cases in which a sufficiently high C peak is necessary to ensure the susceptibility of the pathogens to the drug, 100 mg sitafloxacin once daily should be administered.

Clinical and bacteriological efficacies of sitafloxacin against community-acquired pneumonia caused by Streptococcus pneumoniae: nested cohort within a multicenter clinical trial.

We evaluated the clinical and bacteriological efficacy of oral sitafloxacin (STFX) in clinically diagnosed community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae. Additionally, we cultured these patient samples to test the minimal inhibitory concentrations (MICs) of levofloxacin (LVFX), moxifloxacin (MFLX), STFX, and penicillin G (PCG), as well as identified mutations in the quinolone resistance determinant regions (QRDRs) in LVFX-resistant strains. This study is a nested cohort from a prospective, multicenter clinical trial consisting of 139 patients with community-acquired pneumonia (CAP), from which 72 were included in this study. After diagnosis of CAP caused by S. pneumoniae, STFX (50 mg twice daily, or 100 mg once daily) was orally administered for 7 days. Sixty-five patient sputum samples were then cultured for MIC analysis. In a LVFX-resistant strain that was identified, mutations in the QRDRs of the gyrA, gyrB, parC, and parE genes were examined. Of 72 patients eligible for this study, S. pneumoniae was successfully cultured from the sputum of 65 patients, and only 7 patients were diagnosed by urinary antigen only. Clinical improvement of CAP was obtained in 65 of the 69 clinically evaluable patients (65/69, 94.2 %). Eradication of S. pneumoniae was observed in 62 patients of the 65 bacteriologically evaluable patients (62/65, 95.4 %). Additionally, STFX showed the lowest MIC distribution compared with LVFX, MFLX, and PCG, and no major adverse reactions were observed. STFX treatment in patients with CAP caused by S. pneumoniae was found to be highly effective both clinically (94.2 %) and bacteriologically (95.4 %).

A case of NDM-1-producing Acinetobacter baumannii transferred from India to Japan.

A 52-year-old male Japanese businessman with massive cerebral bleeding was transferred from India to Japan and was admitted to our hospital. Multidrug-resistant Acinetobacter baumannii was isolated from his sputum. The minimum inhibitory concentrations for this strain were as follows: imipenem, 64 µg/ml; meropenem, 32 µg/ml; ciprofloxacin, 16 µg/ml; amikacin, 16 µg/ml; aztreonam, 16 µg/ml; colistin, <1 µg/ml. This A. baumannii strain had both bla NDM-1 and bla OXA-23 by polymerase chain reaction analysis. In Japan, NDM-1-producing bacteria are extremely rare in clinical specimens. To date, three NDM-1-positive cases have been detected in Japan, and this is the first case of A. baumannii-producing NDM-1 in Japan. Our case suggests that NDM-1-producing bacteria could be introduced into our country easily. There is concern that various resistant bacteria may be transferred from epidemic countries as a result of international medical care.

[Safety and pharmacokinetics of 400 and 600 mg arbekacin sulfate to healthy male volunteers].

We assessed the safety and pharmacokinetics of arbekacin sulfate (ABK, brand name: Habekacin injection) in single and 7-day multiple administration of ABK 400 and 600 mg as potency to healthy male volunteers. In the single administration of ABK 400 and 600 mg (over 30 min, drip infusion), C(max) values were 41.0 +/- 3.6 microg/mL and 63.0 +/- 9.9 microg/mL, respectively. Serum ABK concentrations at 60 min (C(peak)) after the start of administration were 23.2 +/- 2.9 microg/mL and 38.5 +/- 3.3 microg/mL, respectively, and the mean serum ABK concentrations at 24 hr (C(trough)) after the start of administration were less than 0.4 microg/mL (LOQ: limited of quantitation). C(max), Cpeak and AUC(0-infinity) were increased with doses, and t1/2, CL(tot), CL(r) V(ss) and urinary excretion were comparable at both doses. In the multiple administration of ABK 400 and 600 mg (over 30 min, drip infusion) once a day for 7 days, C(max0, C(peak) and AUC(0-infinity) were comparable from the 1st day through to 7th day and increased with doses. After the administration, the serum ABK concentrations were decreased with time, and the means of C(trough) were 0.4 microg/mL (LOQ) -0.5 microg/mL, which showed ABK has no tendency toward accumulation. In addition, t1/2, CL(tot), CL(r) V(ss) and urinary excretion were constant throughout administration days at either dose, and CL(tot) containing CL(r) was not decreased. There were no notable changes in the functions of the kidney, auditory organs, etc. Based on the above-mentioned results, when ABK 400 or 600 mg was intravenously administered over 30 min once or once a day for 7 days to the healthy male volunteers with normal renal clearance, it is suggested there were no problems in terms of safety, and C(max) were 36.7-54.1 and 44.2-78.5 microg/mL, respectively. In addition, C(trough) was 0.5 microg/mL or lower at either doses and ABK was not accumulated in multiple administration of ABK. ABK was, therefore, expected to have good safety profile and favorable pharmacokinetics.

DSP-0509, a systemically available TLR7 agonist, exhibits combination effect with immune checkpoint blockade by activating anti-tumor immune effects.

TLR7 is an innate immune receptor that recognizes single-stranded RNAs, and its activation leads to anti-tumor immune effects. Although it is the only approved TLR7 agonist in cancer therapy, imiquimod is allowed to be administered with topical formulation. Thus, systemic administrative TLR7 agonist is expected in terms of expanding applicable cancer types. Here, we demonstrated the identification and characterization of DSP-0509 as a novel small-molecule TLR7 agonist. DSP-0509 is designed to have unique physicochemical features that could be administered systemically with a short half-life. DSP-0509 activated bone marrow-derived dendritic cells (BMDCs) and induced inflammatory cytokines including type I interferons. In the LM8 tumor-bearing mouse model, DSP-0509 reduced tumor growth not only in subcutaneous primary lesions but also in lung metastatic lesions. DSP-0509 inhibited tumor growth in several syngeneic tumor-bearing mouse models. We found that the CD8+ T cell infiltration of tumor before treatment tended to be positively correlated with anti-tumor efficacy in several mouse tumor models. The combination of DSP-0509 with anti-PD-1 antibody significantly enhanced the tumor growth inhibition compared to each monotherapy in CT26 model mice. In addition, the effector memory T cells were expanded in both the peripheral blood and tumor, and rejection of tumor re-challenge occurred in the combination group. Moreover, synergistic anti-tumor efficacy and effector memory T cell upregulation were also observed for the combination with anti-CTLA-4 antibody. The analysis of the tumor-immune microenvironment by using the nCounter assay revealed that the combination of DSP-0509 with anti-PD-1 antibody enhanced infiltration by multiple immune cells including cytotoxic T cells. In addition, the T cell function pathway and antigen presentation pathway were activated in the combination group. We confirmed that DSP-0509 enhanced the anti-tumor immune effects of anti-PD-1 antibody by inducing type I interferons via activation of dendritic cells and even CTLs. In conclusion, we expect that DSP-0509, a new TLR7 agonist that synergistically induces anti-tumor effector memory T cells with immune checkpoint blockers (ICBs) and can be administered systemically, will be used in the treatment of multiple cancers.

Low level ß-lactamase production in methicillin-resistant staphylococcus aureus strains with ß-lactam antibiotics-induced vancomycin resistance.

BACKGROUND: A class of methicillin-resistant Staphylococcus aureus (MRSA) shows resistance to vancomycin only in the presence of ß-lactam antibiotics (BIVR). This type of vancomycin resistance is mainly attributable to the rapid depletion of free vancomycin in the presence of ß-lactam antibiotics. This means that ß-lactam antibiotics remain active or intact in BIVR culture, although most MRSA cells are assumed to produce ß-lactamase. We hypothesised that the BIVR cells either did not harbour the ß-lactamase gene, blaZ, or the gene was quiescent. We tested this hypothesis by determining ß-lactamase activity and conducting PCR amplification of blaZ. RESULTS: Five randomly selected laboratory stock BIVR strains showed an undetectable level of ß-lactamase activity and were blaZ-negative. Five non-BIVR stock strains showed an average ß-lactamase activity of 2.59 ± 0.35 U. To test freshly isolated MRSA, 353 clinical isolates were collected from 11 regionally distant hospitals. Among 25 BIVR strains, only 16% and 8% were blaZ positive and ß-lactamase-positive, respectively. In contrast, 95% and 61% of 328 non-BIVR strains had the blaZ gene and produced active ß-lactamase, respectively. To know the mechanism of low ß-lactamase activity in the BIVR cells, they were transformed with the plasmid carrying the blaZ gene. The transformants still showed a low level of ß-lactamase activity that was several orders of magnitude lower than that of blaZ-positive non-BIVR cells. Presence of the ß-lactamase gene in the transformants was tested by PCR amplification of blaZ using 11 pairs of primers covering the entire blaZ sequence. Yield of the PCR products was consistently low compared with that using blaZ-positive non-BIVR cells. Nucleotide sequencing of blaZ in one of the BIVR transformants revealed 10 amino acid substitutions. Thus, it is likely that the ß-lactamase gene was modified in the BIVR cells to downregulate active ß-lactamase production. CONCLUSIONS: We concluded that BIVR cells gain vancomycin resistance by the elimination or inactivation of ß-lactamase production, thereby preserving ß-lactam antibiotics in milieu, stimulating peptidoglycan metabolism, and depleting free vancomycin to a level below the minimum inhibitory concentration of vancomycin.